Extinct prehistoric reptile that lived among dinosaurs discovered

Opisthiamimus gregori - Credit: Julius Csotonyi for the Smithsonian Institution - An extinct species of lizard-like reptile that belongs to the same ancient lineage as New Zealand's living tuatara has been discovered by a team involving a UCL researcher. The researchers describe the new species Opisthiamimus gregori , which once inhabited Jurassic North America about 150 million years ago alongside dinosaurs like Stegosaurus and Allosaurus , in a paper published in the Journal of Systematic Palaeontology . In life, this prehistoric reptile would have been about 16 centimetres from nose to tail-and would fit curled up in the palm of an adult human hand-and likely survived on a diet of insects and other invertebrates. Co-author Dr Matthew Carrano (National Museum of Natural History, Smithsonian Institution) said: "What's important about the tuatara is that it represents this enormous evolutionary story that we are lucky enough to catch in what is likely its closing act. Even though it looks like a relatively simple lizard, it embodies an entire evolutionary epic going back more than 200 million years." The discovery comes from a handful of specimens including an extraordinarily complete and well-preserved fossil skeleton excavated from a site centred around an Allosaurus nest in northern Wyoming's Morrison Formation in the US. Further study of the find could help reveal why this animal's ancient order of reptiles were winnowed down from being diverse and numerous in the Jurassic to just New Zealand's tuatara surviving today.